In the last decades, miniaturized sample preparation and analysis units, so called “lab-on-a-chip (LOC)”, were introduced. These devices integrate one or several laboratory functions on a single chip of only millimeters to a few square centimeters in size. Their introduction was, at least in part, motivated by the introduction of nucleic acid hybridization technologies for diagnostic, analytic and forensic purposes, and by the increasing demand for high throughput capacities, which were necessitated by increasingly large sample numbers. The development of these devices has been supported by advancements in lithography-based technologies, as well as by new developments in surface coating technologies.
However, control of liquid flow and/or liquid dispersion is still a problem in lab on a chip devices, due to manufacturing problems, as well as lack of controllability of behaviour of liquids in the micro- and nano scale.
Liu et al (2004) have described a single-use, thermally actuated paraffin valve for microfluidic applications, which has a “close-open” function, i.e., it can only open once (non-pinch-off, or tonic actuation mode). Such valve however requires the use of heat, while the molten paraffin may contaminate the samples located on the device, or clog microchannels on the device.
It is the object of the present invention to provide a device which allows control of liquid flow and/or liquid dispersion in a microfluidic device without the disadvantages described above.
It is another object of the present invention to provide a valve for use in a microfluidic device, which can be opened irreversibly upon actuation.
It is furthermore an object of the present invention to provide methods for the manufacture, and for the use, of such device.
These objects are achieved by the method and as set forth under the independent claims. The dependent claims indicate preferred embodiments. In this context it is noteworthy to mention that all ranges given in the following are to be understood as that they include the values defining these ranges.